Leandro da Costa Rech said:

I am new in this game, so I prefer to ask first the opinion the experient players.  Which champions I NEED to evolve? Thanks.

If you are new i would recommend Kael to level to 6 star. He can be useful all around. Good Luck

Leandro da Costa Rech said:

I am new in this game, so I prefer to ask first the opinion the experient players.  Which champions I NEED to evolve? Thanks.

Keep your starter all the way to 60. The 4 of them are pretty much the best rare attackers... Even better than most epics.

Try to get Valerie in the campaign beginning. She is a amazing support. Her heal grows stronger with the number of buff, so try to get at least one rare that buff all your team.

Try to get executioner, demonist and warmaiden, all farmable in the campaign. If you get more than one, use it as a sacrifice to upgrade your main. Keep the rare books for your starter, or apothecary if you draw him.

This should be a good team for a starter. Keep them until they are lvl 40. If you get an epic that can replace one of them, you will know by then. Remember that a good basic team is composed of attackers that can zone if needed... But when en you receive a rare or an epic, check its skills. Some of the skills might seem irrelevant at first but you ll realize then come handy for certain encounters, notably in dungeons... Heal reduction for spirit keep, remove buff for magic keep...

In the beginning forget the spider and fire knight. Wait to have enough zone and power for the first (around 20k) ... Attackers with multi hit skills for the second. 

I hope it will helped a little. 

Enjoy